The present disclosure relates to the subject matter contained in Japanese Patent Application No. 2001-215498 filed on Jul. 16, 2001, which are incorporated herein by reference in its entirety.
1. Field of the Invention
This invention relates to a vehicle idling stop control apparatus being installed in a vehicle comprising an engine of an internal combustion engine, such as an automobile, for controlling the idling state of the engine.
2. Description of the Related Art
Hitherto, an engine of an automobile has been set so as to continue driving in an idling state of low output even if the opening of a throttle valve is minimized by gas pedal operation. If the engine is stopped at the temporary stopping time, etc., of the vehicle, when operating the engine is restarted, restarting must be conducted, it takes time in operation, and it is feared that it may interfere with rapid starting of driving the vehicle. In such a vehicle, to stop the engine, the driver needs to perform operation to stop the engine, such as operating an ignition key switch. However, it also becomes important to enhance fuel economy in the vehicle to make the efficient use of energy, it becomes necessary to suppress exhaust gases from the environmental issue of preventing global warming, and a request is made not to perform unnecessary idling.
Although unnecessary idling can also be decreased by conscious operation of the vehicle user such as the driver, the load when the vehicle is driven is increased. Then, a system is realized wherein a computer is installed in a vehicle for controlling so as to stop unnecessary idling driving and automatically start when operating the engine is restarted. Related arts to such a system are disclosed in JP-A-8-61110 and JP-A-10-47105, for example.
JP-A-8-61110 discloses an art wherein an engine control apparatus for stopping an engine if the driver does not press down on a gas pedal for a given time or the vehicle speed is zero and restarting the engine if the driver presses down on the gas pedal is used to continue the idling state without stopping the engine when the vehicle stops because of waiting at traffic lights, etc. To make the determination, directional signals, vehicle angle, hill inclination, and the like are entered and if it is predicted that the vehicle will immediately start, the idling state is continued without stopping the engine. JP-A-8-61110 also describes an art wherein to predict whether or not the vehicle will immediately start, route information set in route search made by a navigation system is used and when the vehicle stops at an intersection, etc., it is predicted that the vehicle will immediately start.
JP-A-10-47105 discloses an art for controlling so as to automatically stop an engine if a predetermined engine stop condition becomes true while the engine installed in the vehicle is being operated and automatically start the engine if a predetermined engine start condition becomes true during the automatic stopping. In the related art, the magnitude of the electric load is determined based on the battery voltage and if the battery voltage lowers, the electric load is determined to be large and automatic stopping the engine is inhibited for preventing the electric amount charged in the battery from becoming insufficient, namely, preventing the battery from being dead.
The idling state of the engine contributes to cooling so that the engine does not overheat in continuous running, etc., under high load. Thus, a system for inhibiting stopping of idling when the temperature of cooling water is high is also designed. In JP-A-10-47105, in the second embodiment, the temperature of cooling water is detected by a water temperature sensor and the fact that the water temperature is equal to or greater than a predetermined value is one of the requirements for stopping the engine.
Although it is important to suppress idling of the engine, there is a fear of overheating if the engine is stopped when cooling is required. In the system wherein the cooling water temperature, etc., is detected and when the cooling water temperature, etc., is high, idling stop is inhibited, it is not predicted that the water temperature will rise after continuous running under high load. Thus, if the vehicle is stopped, the water temperature rises to an abnormal high temperature and it becomes necessary to restart the engine for cooling. If the state of an abnormal high temperature occurs repeatedly, an engine failure can occur at the worst.
In the related art described in JP-A-10-47105, the fact that the water temperature of the cooling water of the engine is low is one of the requirements for inhibiting stopping of idling. It is estimated that this measure is taken because it becomes difficult to start the engine if the cooling water temperature of the engine is too low. When the cooling water becomes a high temperature, idling stop is not inhibited and no measures against the state of an abnormal high temperature are taken.
It is an object of the invention to provide a vehicle idling stop control apparatus that can appropriately control idling stop of an engine.
According to the present invention, there is provided a vehicle idling stop control apparatus for controlling whether or not idling stop of an engine of a vehicle is to be inhibited. The vehicle idling stop control apparatus includes a load monitor unit for monitoring run load of the engine and calculating a run load history and a control unit for adding up the run load based on the run load history calculated by the load monitor unit and inhibiting idling stop when the added-up value exceeds a predetermined inhibition determination value.
According to the invention, the vehicle idling stop control apparatus includes the load monitor unit and the control unit to control whether or not operation is to be continued when the vehicle engine is in an idling state. The control unit adds up the run load based on the run load history calculated by the load monitor unit monitoring the run load of the engine and inhibits idling stop if the added-up value exceeds the predetermined inhibition determination value. If the run load continues to be high, idling stop is inhibited, so that the idling operation can be continued for promoting cooling of the engine for avoiding the state of an abnormal high temperature to prevent overheat. Since whether or not idling stop is to be inhibited is determined based on the added-up value of the run load, idling stop can be controlled appropriately in response to the necessity for cooling the engine.
According to the invention, the vehicle idling stop control apparatus further includes an inhibition indication unit for indicating that idling stop is being inhibited when operation of the engine is continued in a state in which idling stop is inhibited by the control unit.
According to the invention, the inhibition indication unit indicates that idling stop is being inhibited, so that the vehicle driver, etc., can understand that it is not incapability of stopping idling because of a system failure, etc., and the driver, etc., can be given no insecure feeling.
According to the invention, the vehicle idling stop control apparatus further includes a temperature sensor for detecting a temperature of a cooling fluid of the engine. The control unit is inputted the temperature of the cooling fluid detected by the temperature sensor and inhibits idling stop of the engine when it is predicted that the temperature will rise exceeding a preset upper limit temperature.
According to the invention, the temperature sensor detects the temperature of the cooling fluid such as engine cooling water and if it is predicted that the detected temperature will rise exceeding the predetermined upper limit temperature, idling stop of the engine is inhibited, so that even if the engine load rises, it can be made hard to enter the state of an abnormal high temperature.